Added 'Extra precision' to report.

simmod/ass1/.gitignore

@@ -9,3 +9,4 @@ report.pdf
 fd*
 pr
 floating_point.tex
+extra_precision.tex

simmod/ass1/Makefile

@@ -6,7 +6,10 @@ OPS=ADD DIV MULT SQRT
 
 all: fp speed highlight report.pdf sum pr
 
-highlight: floating_point.tex
+highlight: floating_point.tex extra_precision.tex
+
+extra_precision.tex: extra_precision.c
+	pygmentize -O style=colorful -o $@ $^
 
 floating_point.tex: floating_point.c
 	pygmentize -O style=colorful -o $@ $^

simmod/ass1/extra_precision.c

 #include <stdio.h>
 
-// Calculate 'e' using
-// e=1+1/1!+1/2!+1/3!+1/4!+...
-// 4! is 4x3x2x1. The series converges rapidly to e.
-// That series comes from this series:
-// ex=1+x/1!+x2/2!+x3/3!+x4/4!+...
-
-int fact(int x) {
-    return x > 0 ? x * fact(x-1) : 1;
-}
+// Calculate 'e' using e=1+1/1!+1/2!+1/3!+1/4!+...
+// 8! is 8x7x6x5x4x3x2x1. The series converges rapidly to e.
+
+int fact(int x) { return x > 0 ? x * fact(x-1) : 1; }
 
 int main(void) {
     float last_e, e;

simmod/ass1/report.tex

@@ -153,6 +153,31 @@ Type            & N              & Forward    & Backward \\
 
 % }}}
 
+\section{Extra precision} % {{{
+\label{sec:Extra precision}
+
+Our machine has an Intel Core2 Duo cpu (cpu type is E6750) running at 2.66GHz.
+Because Intel added the x87 instruction set (a subset of x86), the FPU
+(floating point unit) has a more precise floating point register.
+
+To demonstrate this, we created simple C program, which will approximate the
+constant $e$ twice. The first time it will save the final result in a float, the
+second time it will store the result in the floating point register. The second
+approximation is compared to the first and if the first approximation is large
+than the second, the processor has a more precise floating point register. The
+simple C program is listed in the appendix \ref{sec:extra_precision.c} and
+produces this output:
+
+\begin{verbatim}
+$ ./pr
+more precision detected!
+diff:
+2.6910297870635986328125000000000000000000000000000000000
+2.6910298253667153112189680541632696986198425292968750000
+\end{verbatim}
+
+% }}}
+
 \appendix{}
 
 \section{floating\_point.c} % {{{
@@ -162,5 +187,12 @@ Type            & N              & Forward    & Backward \\
 
 % }}}
 
+\section{extra\_precision.c} % {{{
+\label{sec:extra_precision.c}
+
+\input{extra_precision}
+
+% }}}
+
 
 \end{document}